1. Field of the Invention
The present invention relates to a variable-height device for supporting a boot on a ski.
This type of device is more particularly intended to serve as a support for the standardized smooth zone of the ski-boot sole in order to limit parasitic friction forces which develop between the sole and the ski and in order to prevent these friction forces from disturbing the operation of the safety ski binding. The smooth zone mentioned above is a transverse band 40 millimeters in width. The front edge of the band is located at a distance of 30 millimeters from the toe end of the sole in the case of "adult standard" ski boots and at a distance of 25 millimeters in the case of "child standard" ski boots. It is for this reason that the device is usually integrated with the toe abutment member of a ski binding.
2. Description of the Prior Art
It is a known practice to provide boot-supporting devices which are adjustable for height in order to adapt the safety ski binding to the thickness of the ski boot employed. Provision can accordingly be made for a toe abutment member of a ski binding in which the jaw unit is stationarily fixed in the vertical direction. This not only permits a substantial reduction both in cost price and in bulk of the toe abutment member but also removes the disadvantage of lateral play which is almost inevitably encountered in jaw units which permit height adjustment.
Thus the ski-boot supporting device described in U.S. Pat. No 4,135,736 comprises a vertically displaceable support plate. Adjustment of the plate is performed by wedge effect by longitudinal displacement either of the support plate itself (FIG. 2) or one or two control elements placed beneath the support plate (FIGS. 3, 4, 6).
In the first embodiment of FIG. 2, height adjustment of the support plate entails the need for modification of its position on the ski in the longitudinal direction. In consequence, the support plate is not located continuously opposite to the standardized smooth zone of the skiboot sole, which is unsatisfactory from a safety standpoint.
In the other embodiments of FIGS. 3, 4 and 6, height adjustment of the support plate calls for preliminary slackening of the screws which serve to fix the device on the ski. The screws are thus re-tightened after suitable displacement of the control element (or elements). Now it is a well-established fact that repeated screwing and unscrewing operations performed on screws of the type employed in skis (wood-screws) eventually result in damage to the holes in which they are fitted. This is therefore a disadvantage, especially in the case of skis for hire since height adjustment operations on hired skis are frequent.
Moreover, the forms of construction which appear in the U.S. patent cited in the foregoing all suffer from a common drawback in that access to the screws and correlative height adjustment are possible only if the boot is not in position in the ski-binding. Adjustment therefore takes place by trial and error, which is somewhat irrational as well as time-consuming and is a disadvantage for the operator.
The supporting device in accordance with Certificate of Utility FR. No. 2,431,306 is similar in design to the device which has just been described and consequently suffers from the same drawbacks.
In another known boot-supporting device disclosed in patent AT. No. 368,900, height adjustment is apparently possible when the boot is in position within the ski-binding. This adjustment does not make it necessary to unscrew and re-tighten fixing screws. Locking of the support plate in the desired position is in fact achieved by means of a locking tooth formed on a resilient strip which cooperates with a set of teeth carried by a backpiece.
Unfortunately, this device is again not wholly satisfactory by reason of the fact that, as in the first embodiment (FIG. 2) of the U.S. patent mentioned earlier, height adjustment entails the need for longitudinal displacement of the support plate. Furthermore, resilient locking of the support plate by means of a single resilient tooth appears distinctly insufficient to remove any danger of accidental disadjustment of the system while skiing is in progress.